Alarm safety-valve.



' No. 722,047. PATENTED MAR. 3. 1903.

L. RO BISON & J. SHAFER.

ALARM SAFETY VALVE. APPLIOATION FILED MAR. 1, 1902'.

F0 MODEL.

- 2366720556070. M J wen as on. PHOTO-H1941. WASHINGT same with whistle removed.

irnn STATES i Prion.

PATENT ALARM SAFETY-VALVE.

SPECIFICATION forming part of Letters Patent No. 722,047, dated March 3, 1903.

Application filed March 1, 1902.

To all whom it may concern.-

Be it known that we, LEE ROBISON and JAMES SHAFER, citizens of the United States, residing at Huntington, in the county of Huntington and State of Indiana, have invented new and useful Improvements in Alarm Safety-Valves, of which the following is a specification.

Our invention relates to alarm safety-valves for fluid-pressure systems, such as air and steam; and the object of the same is to construct a safety-valve provided with a whistle which will sound an alarm when the valve blows This form of valve will be particularly useful as an adjunct to air-brake systems.

The novel construction employed by us in carrying out our invention is fully described in this specification and claimed, and illustrated in the accompanying drawings, forming a part thereof, in which- Figure 1 is a side elevation of our device. Fig. 2 is avertical longitudinal section of the Like numerals of reference designate like parts in both views of the drawings.

The numeral 1 designates a cylindrical casing, which is screwed into a lower head 2, having an internally-threaded flange 3 thereon. The head 2 is centrally apertured at 4 and has a threaded connection 5 formed integral therewith, which is designed to be connected to a system using air under high pressure. A head 6, bearing an externallythreaded rim 7, is fitted in the upper end of the cylinder 1. This head 6 is apertured at 8 and is provided with a threaded connection 8, which is connected to a whistle 9 of ordinary form.

A valve 10 is slidingly mounted in the cylinder and comprises a snugly-fitting piston 11, bearing a stem 12. The piston 11 is grooved at 13 to accommodate a packing-ring 14. The stem 12 slides in a guide 15, screwed into the casing 1. The guide 15 is apertured at 16 to permit the passage of air and to accommodate a spanner-wrench for turning the head 15 to adjust the stress of a spring 17. The spring 17 surrounds the stem 12 and bears at its lower end on the piston 11 and at its upper end on the guide 15. The spring 17 holds the piston 11 normally seated on a Serial No. 96,295. (No model.)

shoulder 2, keeps the piston 11 from covering the mouth of the aperture 4:, and thereby gives the air direct action on almost the hole area of the piston. The pop of the valve could be intensified by increasing the area of the shoulder 2. The piston 11 when seated closes the lower ends of two short grooves 18, cut in the sides of the casing 1 to form ports to permit the passage of air past the piston 11. A downwardly extending cylindrical portion 19, formed on the guide 15, limits the upward movement of the piston.

In operation our valve is connected to an air system and the spring 17 adjusted by means of the guide 15, so that the valve 11 is raised up in contact with the lower end of the guide member 15 when the air in the system is at ordinary service-pressure. When the air falls below the service-pressure, the valve 11 will occupy a position intermediate its seat and the uppermost position and will simultaneously uncover both ends of the grooves 18, thereby permitting air to pass through and sound the whistle 9, thereby giving the alarm and notifying the train hands that the braking pressure is below the safety braking pressure. When the pressure falls very low, the valve 11 will be seated.

We do not wish to be limited as to details of construction, as these may be modified in many particulars without departing from the spirit of our invention.

Having described our invention, what we claim as new, and desire to secure by Letters Patent, is-

1. In an alarm safety-valve, the combination with a cylindrical casing having short longitudinally-extending grooves therein located to serve as ports, a lower head mounted in said casing and constructed to be connected to an air system, said head having a shoulder thereon, an adjustable guide fitting said cylinder and having apertures therein, a valve slidingly mounted in said cylinder and bearing a stem fitting an aperture in said guide, said piston being constructed to be normally seated on said shoulder and prevent the passage of air through said grooves, a spring surrounding said stem and bearing on said guide and said valve, and a whistle connected to the upper end of said casing, substantially as described.

2. In an alarm safety-valve, the combination with a cylindrical casing having grooves therein located to serve as ports, a valve slidingly mounted in said casing and provided with a stem, a guide member adjustably mounted in said casing and having an aperture therein through which said stem passes, said guide having a cylindrical portion which serves as a stop for said valve, a spring surrounding said stem and bearing on said guide to hold said valve normally seated, substantially as described.

3. In an alarm-valve, a casing having internal grooves therein located to serve as ports, a whistle connected to said casing, a valve slidingly mounted in said casing and bearing a stem, a guide member engaging said stem 

